CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

In ΔABC, sinAcosBcosC+sinBcosCcosA+sinCcosAcosB is equal to


A
cosAcosBcosC
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
sinAsinBsinC
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
0
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
None of these
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is B sinAsinBsinC
In ABC,A+B+C=π

A+B=πC ...... (i)

Consider,

sinAcosBcosC+sinBcosCcosA+sinCcosAcosB

=cosC(sinAcosB+cosAsinB)+sinCcosA.cosB

=cosC.sin(A+B)+sinC.cosA.cosB

=cosC.sin(πC)+sinC.cosA.cosB ...... From (i)

=sinC.cosC+sinC.cosAcosB

=sinC[cosC+cosA.cosB]

=sinC[cos(π(A+B))+cosA.cosB]

=sinC[cosA.cosBcos(A+B)]

=sinC[cosA.cosB(cosA.cosBsinA.sinB)]

=sinC[sinA.sinB]

=sinA.sinB.sinC.

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Angle and Its Measurement
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon